Dissolvable rubber

ABSTRACT

A degradable elastomeric material that is formed from a composite blend of elastomeric particles in a continuous degradable binder. The degradable binder is generally a water-soluble binder which has a temperature dependent solubility in water and brine systems. Such degradable elastomers are particularly useful in the fabrication of degradable oil tools, among other applications.

The present invention is a continuation of U.S. patent application Ser.No. 15/592,325 filed May 11, 2017, which in turn claims priority on U.S.Provisional Application Ser. No. 62/344,127 filed Jun. 1, 2016, which isincorporated herein by reference.

The present invention relates to a degradable elastomer compositionhaving a controlled microstructure/morphology in that discreteelastomeric particles are dispersed in a continuous liquid-solublebinder phase.

BACKGROUND OF THE INVENTION

Degradable oil tools have been developed which allow for temporaryisolation of wellbores and which can be removed without interventionsuch as retrieval or drilling from the surface. These tools aregenerally fabricated from dissolvable or degradable metals or polymers,including degradable Al, Zn, and Mg alloys, and water-degradablepolymers such as PVA, PLA and PGA. However, these degradable materialsare not generally elastomeric, and non-degradable elastomeric seals areused to provide sealing against fluid flow.

Elastomeric sealing compounds that dissolve and degrade at rates similarto those of the degradable structural alloys (such as Tervalloy™), arestable for the period of operation under low temperatures during pumpingoperations, and degrade at high shut-in or flowback temperatures toreduce or eliminate any residual debris are desired. Such dissolvable,structural elastomeric materials are not readily available, and do nothave the properties required or desired.

Biodegradable polymers and films have been developed that are formedfrom a water-dispersible polymer. For example, U.S. Pat. No. 6,296,914(to Kerins et al.) describes a water-sensitive film that may include,for instance, polyethylene oxide, ethylene oxide-propylene oxidecopolymers, polymethacrylic acid, polymethacrylic acid copolymers,polyvinyl alcohol, poly(2-ethyl oxazoline), polyvinyl methyl ether,polyvinyl pyrrolidone/vinyl acetate copolymers, methyl cellulose, ethylcellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose,ethyl hydroxyethyl cellulose, methyl ether starch, poly (n-isopropylacrylamide), poly N-vinyl caprolactam, polyvinyl methyl oxazolidone,poly (2-isopropyl-2-oxazoline), poly (2,4-dimethyl-6-triazinylethylene), or a combination thereof. Some of these polymers, however,are not thermoplastic or moldable and, thus, are not readily processedusing molding equipment. Further, these elastomers are also not elasticand, thus, may be limited in their use when considered for sealingapplications.

In response to these and other problems with prior art elastomericsealing compounds, attempts have been made to form water-shrinkablematerials from elastomeric and water-dispersible polymers. One suchelastomer is described in U.S. Pat. No. 5,641,562 to (Larson et al.). Inone example, the elastomer contains polyethylene oxide having amolecular weight of about 200,000 and an ethylene vinyl acetatecopolymer. Although such elastomers are shrinkable, they neverthelessare not dispersible or disintegrable in water so as to achieve completeflushability. Furthermore, the elastomers are not truly elastic.

A more recent elastomeric biodegradable film described in U.S. Pat. No.8,338,508 (to Shi et al.) describes a water-sensitive film containing anolefinic elastomer that is both elastic and water-sensitive (e.g.,water-soluble, water-dispersible, etc.) in that it loses its integrityover time in the presence of water. To achieve these dual attributes,the film contains an olefinic elastomer and a water-soluble polymer.Although these polymers are normally chemically incompatible due totheir different polarities, Shi discloses that phase separation can beminimized by selectively controlling certain aspects of the elastomer,such as the nature of the polyolefin, water-soluble polymer, and otherelastomer components, the relative amount of the elastomer components,and so forth. For example, certain water-soluble polymers that have alow molecular weight and viscosity can be selected to enhance their meltcompatibility with nonpolar polyolefins. This, in turn, may result in afilm that is generally free of separate phases, which would otherwiselimit the ability of the water-soluble polymer to contact water anddisperse. As such, Shi discloses the maintaining of the elastomeric anddissolvable components in a single phase, using chemistry developmentsto prevent segregation. These materials are suitable for use in the formof films, but do not have the structural properties required for highpressure sealing applications and cannot be fabricated into bulkobjects.

In view of the current state of elastomeric materials, there is a needfor an elastomeric material that dissolves and degrades at rates similarto those of the degradable structural alloys (such as Tervalloy™), whichare stable for the period of operation under lower temperatures duringpumping operations, and which degrades at high shut-in or flowbacktemperatures to reduce or eliminate any residual debris of theelastomeric materials in the wellbore.

SUMMARY OF THE INVENTION

The present invention is directed to an elastomeric composite materialthat is water-dispersable into fine particles which can be readilyflushed from a wellbore or other system. The elastomeric material of thepresent invention is readily formable into structural seals, includingO-rings, Chevron seals, and washers suitable for the sealing of oil andgas wells and other applications when designed into appropriate sealgeometries and closures. However, it can be appreciated that theelastomeric material can be formed into other types of structures.

As used herein, the term “elastomeric” and “elastic” refers to amaterial that, upon application of a stretching force, is stretchable inat least one direction and which, upon release of the stretching force,contracts/returns to approximately its original dimension. As definedherein, an elastomeric material is a material that has a stretchedlength that is at least 20% greater than its relaxed unstretched length,and which material will recover to within at least 30% of its stretchedlength upon release of the stretching force. For example, a one-inchsample of a material that is stretchable to at least 1.2 inches andwhich, upon release of the stretching force, recovers to a length of1.14 inches or less is defined as an elastomeric material. Generally,the elastomeric material will have a stretched length that is at least30% greater than its relaxed unstretched length, and typically at least50% greater than its relaxed unstretched length, and will recover to50-100% (and all values and ranges therebetween) of its stretched lengthupon release of the stretching force, and typically within 80-100% ofits stretched length upon release of the stretching force.

As used herein the terms “extensible” or “extensibility” refers to amaterial that stretches or extends in the direction of an applied forceby at least about 20% of its relaxed length or width, typically at 30%of its relaxed length or width, and more typically at least 50% of itsrelaxed length or width. An extensible material does not necessarilyhave recovery properties. For example, an elastomeric material is anextensible material having recovery properties. An elastomer can beextensible, but not have recovery properties (e.g., does not recover towithin at least 30% of its stretched length upon release of thestretching force), and thus, be an extensible, non-elastic material.

As used herein, the term “percent stretch” is defined as the degree towhich a material stretches in a given direction when subjected to acertain force. In particular, percent stretch is determined by measuringthe increase in length of the material in the stretched dimension,dividing that value by the original dimension of the material, and thenmultiplying by 100.

As used herein, the term “set” refers to retained elongation in amaterial sample following the elongation and recovery, i.e., after thematerial has been stretched and allowed to relax during a cycle test.

The elastomeric material in accordance with the present inventionincludes elastomer and water-soluble polymer and/or water-reactivepolymer, and optionally one more of plasticizer, compatibilzer, and/oradditional components. The elastomeric material is at least a two-phasesystem wherein a first phase includes water-soluble polymer and a secondphase includes elastomer. The one or more plasticizer, compatibilzer,and/or optional additional components can be included in the firstand/or second phases, or can form a third or fourth phase in theelastomeric material.

SUMMARY OF THE FIGURES

FIG. 1 illustrates various types of types of hydrolysis reactions.

FIG. 2A is a picture of a plug of elastomeric material in accordancewith the present invention.

FIG. 2B is a picture of the plug of elastomeric material illustrated inFIG. 2A that has been degraded.

FIG. 2C is graph of the hardness of the elastomeric material illustratedin FIG. 2A as a function of time as the elastomeric material isdegraded.

FIG. 3 is a picture of an extruded filament formed from the elastomericmaterial in accordance with the present invention.

FIG. 4 is a picture of a seal that was formed from the elastomericmaterial in accordance with the present invention.

FIG. 5A is a picture of a plug of elastomeric material in accordancewith the present invention.

FIG. 5B is a picture of the plug of elastomeric material illustrated inFIG. 2A that has been degraded.

FIG. 5C is graph of the hardness of the elastomeric material illustratedin FIG. 2A as a function of time as the elastomeric material isdegraded.

FIG. 6 is a picture of a seal that was formed from the elastomericmaterial in accordance with the present invention.

FIG. 7 is an illustration of an elastomeric material in accordance withthe present invention formed from elastomeric particles in a dissolvablematrix.

FIG. 8 is an illustration of an elastomeric material in accordance withthe present invention formed from elastomeric particles in a watersoluble matrix with the entire composite surrounded by a protectivecoating.

FIG. 9 is an illustration of an elastomeric material in accordance withthe present invention formed from a dissolving matrix with elastomericparticles and mechanically reinforcement from particles or fibers.

A. Elastomer

The elastomeric material can include one or more elastomers. Theelastomer can constitute about 5 vol. % to about 90 vol. % of theelastomeric material (and all values and ranges therebetween). In onenon-limiting embodiment, the elastomer constitutes about 15 vol. % toabout 80 vol. % of the elastomeric material. In another non-limitingembodiment, the elastomer constitutes about 20 vol. % to about 75 vol. %of the elastomeric material. In another non-limiting embodiment, theelastomer constitutes about 15 vol. % to about 60 vol. % of theelastomeric material. In another non-limiting embodiment, elastomergenerally constitutes the greatest weight percent of any of thecomponents of the elastomeric material. In another non-limitingembodiment, the elastomer constitutes at least 50 vol. % of theelastomeric material. Generally, the elastomer contributes at leastabout 80% of the hardness and mechanical response to the elastomericmaterial; however, this is not required.

Elastomer-Olefinic

Thermoplastic rubbers are well suited to forming/molding into complexshapes. These thermoplastic rubbers are typically mixtures of a rubberphase and a thermoplastic phase such as, but not limited to,polyethylene and/or polypropylene. Olefinic rubbers includepolybutadienes, polyisobutylene (PIB), ethylene propylene rubber (EPR),ethylene propylene diene monomer (M-class) rubber (EPDM rubber), andothers.

Various olefinic elastomers can be employed in the degradable elastomerof the present invention. In one non-limiting embodiment, the olefinicelastomer is a polyolefin that has or is capable of exhibiting asubstantially regular structure (“semi-crystalline”). Such olefinicelastomers can be substantially amorphous in their underformed state,but can form crystalline domains upon stretching. The degree ofcrystallinity of the olefin polymer can be about 3% to about 30% (andall values and ranges therebetween), in some embodiments about 5% toabout 25%, and in some embodiments about 5% and about 15%. Likewise, theolefinic elastomer can have a latent heat of fusion (ΔH_(f)), which isanother indicator of the degree of crystallinity, of about 15 to about75 Joules per gram (“J/g”) (and all values and ranges therebetween), insome embodiments about 20 to about 65 J/g, and in some embodiments about25 to about 50 J/g. The olefinic elastomer may also have a Vicatsoftening temperature of about 10° C. to about 100° C. (and all valuesand ranges therebetween), in some embodiments about 20° C. to about 80°C., and in some embodiments about 30° C. to about 60° C. The olefinicelastomer can have a melting temperature of about 20° C. to about 120°C. (and all values and ranges therebetween), in some embodiments about35° C. to about 90° C., and in some embodiments about 40° C. to about80° C. The latent heat of fusion (ΔT_(f)) and the melting temperature ofthe olefinic elastomer can be determined using differential scanningcalorimetry (DSC) in accordance with ASTM D-3417 as is well known tothose skilled in the art. The Vicat softening temperature can bedetermined in accordance with ASTM D-1525.

Exemplary semi-crystalline olefinic elastomers that can be used in thedegradable elastomer of the present invention include polyethylene,polypropylene, blends and copolymers thereof. In one non-limitingembodiment, a polyethylene is employed that is a copolymer of ethyleneand an α-olefin, such as, but not limited to, a C₃-C₂₀ α-olefin and/orC₃-C₁₂ α-olefin. Suitable α-olefins can be linear or branched (e.g., oneor more C₁-C₃ alkyl branches, or an aryl group). Specific examplesinclude 1-butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene;1-pentene with one or more methyl, ethyl or propyl substituents;1-hexene with one or more methyl, ethyl or propyl substituents;1-heptene with one or more methyl, ethyl or propyl substituents;1-octene with one or more methyl, ethyl or propyl substituents; 1-nonenewith one or more methyl, ethyl or propyl substituents; ethyl, methyl ordimethyl-substituted 1-decene; 1-dodecene; and styrene. Particularlydesirable α-olefin comonomers are 1-butene, 1-hexene and 1-octene. Theethylene content of such copolymers can be about 60 mole % to about 99mole % (and all values and ranges therebetween), in some embodimentsabout 80 mole % to about 98.5 mole %, and in some embodiments about 87mole % to about 97.5 mole %. The α-olefin content may likewise rangeabout 1 mole % to about 40 mole % (and all values and rangestherebetween), in some embodiments about 1.5 mole % to about 15 mole %,and in some embodiments about 2.5 mole % to about 13 mole %. Propylenepolymers may also be suitable for use as an olefinic elastomer. In onenon-limiting embodiment, the semi-crystalline propylene-based polymerincludes a copolymer of propylene and an α-olefin, such as, but notlimited to, a C₂-C₂₀ α-olefin and/or C₂-C₁₂ α-olefin. Particularlydesired are α-olefin comonomers of ethylene, 1-butene, 1-hexene and1-octene. The propylene content of such copolymers can be about 60 mole% to about 99.5 vol. % (and all values and ranges therebetween), in someembodiments about 80 mole % to about 99 mole %, and in some embodimentsabout 85 mole % to about 98 mole %. The α-olefin content can likewise beabout 0.5 mole % to about 40 mole % (and all values and rangestherebetween), in some embodiments about 1 mole % to about 20 mole %,and in some embodiments about 2 mole % to about 15 mole %. Somenon-limiting suitable polyolefin plastomers are available under thedesignation ENGAGE™ and AFFINITY™ from Dow Chemical Company of Midland,Mich.

Elastomer-Ethylene

Some non-limiting ethylene elastomers that can be used in the presentinvention are ethylene-based copolymer plastomers available under theEXACT™ from ExxonMobil Chemical Company of Houston, Tex. (ethyleneoctane copolymer—ethylene based plastomer resin). Still other suitableethylene polymers are available from The Dow Chemical Company under thedesignations DOWLEX™ (Linear low-density polyethylene—LLDPE) and ATTANE™(Ultra Low Density Polyethylene—ULDPE). Such ethylene polymers aredescribed in U.S. Pat. No. 4,937,299 to Ewen et al. (polymer blends ofpolyethylenes such as high density polyethylene (HDPE) and linear lowdensity polyethylene (LLDPE) and with copolyethylene higheralpha-olefins having from 3 to about 10 carbon atoms and preferably 4 to8 carbon atoms. Illustrative of the higher alpha-olefins are propylene,butene-1, hexene-1 and octene-1. Preferably, the alpha-olefin ispropylene or butene-1); U.S. Pat. No. 5,218,071 to Tsutsui et al.(ethylene copolymers formed from ethylene and α-olefins of 3-20 carbonatoms are copolymerized so that a density of the resulting copolymersbecomes 0.85-0.92 g/cm³); U.S. Pat. No. 5,272,236 to Lai et al. (Asubstantially linear olefin polymer characterized as having: a) a meltflow ratio, I₁₀/I₂, ≥5.63, b) a molecular weight distribution,M_(w)/M_(n), defined by the equation: M_(w)/M_(n)≤(I₁₀/I₂)−4.63, and c)a critical shear stress at onset of gross melt fracture of greater thanabout 4×10⁶ dyne/cm², wherein the olefin polymer is furthercharacterized as a copolymer of ethylene with a C₃-C₂₀ alpha-olefin);and U.S. Pat. No. 5,278,272 to Lai et al. (A substantially linear olefinpolymer characterized as having: a) a melt flow ratio, I₁₀/I₂, ≥5.63, b)a molecular weight distribution, M_(w)/M_(n), defined by the equation:M_(w)/M_(n)≤(I₁₀/I₂)−4.63, and c) a critical shear rate at onset ofsurface melt fracture of at least 50 percent greater than the criticalshear rate at the onset of surface melt fracture of a linear olefinpolymer having about the same I₂ and M_(w)/M_(n), and wherein the olefinpolymer is further characterized as a copolymer of ethylene with aC₃-C₂₀ alpha-olefin), which are all incorporated herein in by reference.Suitable propylene polymers are commercially available under thedesignations VISTAMAXX™ (Polyolefin Copolymer/Terpolymer) fromExxonMobil Chemical Co. of Houston, Tex.; FINA™ (e.g., FINA™ 8573) fromAtofina Chemicals of Feluy (a low melting, high ethylene randomcopolymer), Belgium; TAFMER™ available from Mitsui PetrochemicalIndustries (low crystalline or amorphous α-olefin copolymer); andVERSIFY™ available from Dow Chemical Co. of Midland, Mich.(propylene-ethylene copolymers). Other examples of suitable propylenepolymers are described in U.S. Pat. No. 6,500,563 to Datta et al. (Apolymer formed by: (a) polymerizing propylene or a mixture of propyleneand one or more monomers selected from C₂ or C₃-C₂₀ alpha olefins in thepresent of a polymerization catalyst wherein a substantially isotacticpropylene polymer containing at least 90% by weight polymerizedpropylene is obtained to form a propylene polymer; (b) polymerizing amixture of ethylene and propylene in the presence of a chiralmetallocene catalyst, wherein a crystallizable copolymer of ethylene andpropylene is obtained comprising up to 35% by weight ethylene,containing isotactically, crystallizable propylene sequences; and (c)blending the propylene polymer of step (a) with the crystallizablecopolymer of step (b) to form a blend); U.S. Pat. No. 5,539,056 to Yanget al. (a polypropylene blend composition comprising about 60 to about90 weight percent of an amorphous polypropylene having a Mw of at leastabout 150,000 and a Mw/Mn of about 3 or less and from about 40 to 10weight percent of a crystalline isotactic polypropylene having a Mw ofless than about 300,000, provided that the Mw of the amorphouspolypropylene is greater than the Mw of the crystalline isotacticpolypropylene); and U.S. Pat. No. 5,596,052 to Resconi et al., all ofwhich are incorporated herein by reference.

As can be appreciated, other or additional olefinic elastomers can alsobe used in the present invention. In one non-limiting embodiment, thethermoplastic elastomer can be a styrene-olefin block copolymer, suchas, but not limited to, styrene-(ethylene-butylene),styrene-(ethylene-propylene), styrene-(ethylene-butylene)-styrene,styrene-(ethylene-propylene)-styrene,styrene-(ethylene-butylene)-styrene-(ethylene-butylene),styrene-(ethylene-propylene)-styrene-(ethylene-propylene), andstyrene-ethylene-(ethylene-propylene)-styrene. Such polymers can beformed by selective hydrogenation of styrene-diene block copolymers,such as described in U.S. Pat. Nos. 4,663,220; 4,323,534; 4,834,738;5,093,422; and 5,304,599, all of which are hereby incorporated byreference. Particularly suitable thermoplastic elastomers are availablefrom Kraton Polymers LLC of Houston, Tex. under the trade name KRATON®.Other commercially available block copolymers include the S-EP-Selastomeric copolymers available from Kuraray Company, Ltd. of Okayama,Japan, under the trade designation SEPTON®. Also suitable are polymerscomposed of an A-B-A-B tetrablock copolymer such as discussed in U.S.Pat. No. 5,332,613 to Taylor et al., which is incorporated herein byreference. An example of such a tetrablock copolymer is a styrene-poly(ethylene-propylene)-styrene-poly (ethylene-propylene) (“S-EP-S-EP”)block copolymer.

Elastomer-Vulcanized

Another type of elastomers that can be used in the present invention istraditional vulcanized (thermoset) elastomers, such as, but not limitedto, all forms of silicone rubber, urethane rubber, natural rubber,nitrile rubber, and fluoropolymer rubbers. Nitrile rubbers (NBR) andhydrogenated nitrile rubbers, vinylidene fluoride CO and terpolymersFKM), propylene-tetrafluoroethylene (FEPM, AFLAS®), andperfolouroelastomers (FFKM, Kalrez®, CHEMRAZ®) can be used with suitableadhesive additions.

Elastomer-Powdered Nitrile Rubber

Powdered nitrile rubber such as NBR (Baymod®, Nipol® and Nitroflex) canalso be used as a basic elastomeric element. The T_(g) of thesematerials is in the range of −30 C to −40 C. Nitrile rubber can also bemixed with acrylate-butadiene rubber (ABR) or styrene-butadiene rubber(SBR) which can be used as filler. There is also an opportunity tore-use rubber from scrap tires which can be a great asset to theenvironment.

In one non-limiting embodiment, one or more of the elastomers used inthe elastomeric material are selected from the group consisting ofnatural rubber, vulcanized rubber, silicone, polyurethane, syntheticrubber, polybutadiene, powdered NBR (with different acrylonitrilecontents), polyisobutylene, acrylate-butadiene rubber, and styrenebutadiene rubber.

B. Water-Soluble Or Water-Reactive Polymer

The elastomeric material includes one or more water-soluble (WS)polymers and/or water-reactive (WR) polymers. The water-soluble polymersand/or water-reactive polymers constitutes about 5 vol. % to about 60vol. % of the elastomeric material (and all values and rangestherebetween), typically about 8 vol. % to about 45 vol. % of theelastomeric material, more typically about 20 vol. % to about 40 vol. %of the elastomeric material, and even more typically about 20 vol. % to35 vol. %.

The water-soluble polymer and/or water-reactive polymer generally haslow solubility below about 30° C. and increased solubility at about 55°C.−180° C. (and all values and ranges therebetween) when exposed toliquids typically used in fracking environments (e.g., water, brine,fracking additives, and/or oil), a polymer that is degradable byhydrolysis or solvates into soluble elements such as monomers orchemically altered soluble polymers. Generally, the water-solublepolymer and/or water-reactive polymer has an acceptable degradation rate(e.g., degrades at least 10% within 2-3 hours) at least 55° C., or atleast 70° C., or at least 100° C., or at least 110° C., or at least 135°C., or at least 180° C., and has low or essentially no reactivity (doesnot dissolve or degrade) at temperatures below about 30° C. (degradesless than 1% after 5 hours).

Such water-soluble polymers and/or water-reactive polymers can be formedfrom monomers such as, but not limited to, vinyl pyrrolidone,hydroxyethyl acrylate or methacrylate (e.g., 2-hydroxyethylmethacrylate), hydroxypropyl acrylate or methacrylate, acrylic ormethacrylic acid, acrylic or methacrylic esters or vinyl pyridine,acrylamide, vinyl acetate, vinyl alcohol (hydrolyzed from vinylacetate), ethylene oxide, polyvinylpyrrolidone derivatives thereof, andso forth. Other examples of suitable monomers are described in U.S. Pat.No. 4,499,154 to James et al., which is incorporated herein byreference. The resulting water-soluble polymers and/or water-reactivepolymers can be homopolymers or interpolymers (e.g., copolymer,terpolymer, etc.), and can be nonionic, anionic, cationic, oramphoteric. In addition, the water-soluble polymers and/orwater-reactive polymers can be of one type (i.e., homogeneous), ormixtures of different water-soluble polymers can be used (i.e.,heterogeneous). In one non-limiting embodiment, the water-solublepolymers and/or water-reactive polymers contains a repeating unit havinga functional hydroxyl group, such as, but not limited to, polyvinylalcohol (PVOH), copolymers of polyvinyl alcohol (e.g., ethylene vinylalcohol copolymers, methyl methacrylate vinyl alcohol copolymers, etc.),etc. Vinyl alcohol polymers, for instance, have at least two or morevinyl alcohol units in the molecule and can be a homopolymer of vinylalcohol, or a copolymer containing other monomer units. Vinyl alcoholhomopolymers can be obtained by hydrolysis of a vinyl ester polymer,such as, but not limited to, vinyl formate, vinyl acetate, vinylpropionate, etc. Vinyl alcohol copolymers can be obtained by hydrolysisof a copolymer of a vinyl ester with an olefin having 2 to 30 carbonatoms, such as, but not limited to, ethylene, propylene, 1-butene, etc.;an unsaturated carboxylic acid having 3 to 30 carbon atoms, such as, butnot limited to, acrylic acid, methacrylic acid, crotonic acid, maleicacid, fumaric acid, etc., or an ester, salt, anhydride or amide thereof;an unsaturated nitrile having 3 to 30 carbon atoms, such as, but notlimited to, acrylonitrile, methacrylonitrile, etc.; a vinyl ether having3 to 30 carbon atoms, such as, but not limited to, methyl vinyl ether,ethyl vinyl ether, etc.; and so forth.

The degree of hydrolysis can be selected to obtain a desired solubility,etc., of the water-soluble polymers and/or water-reactive polymers. Forexample, the degree of hydrolysis can be about 60 mole % to about 95mole % (and all values and ranges therebetween), in some embodimentsabout 80 mole % to about 90 mole %, and in some embodiments about 85mole % to about 89 mole %. Examples of suitable partially hydrolyzedpolyvinyl alcohol polymers are available under the designation CELVOL™from Celanese Corp. Other suitable partially hydrolyzed polyvinylalcohol polymers are available under the designation ELVANOL™ fromDuPont. SELVOL™ from Sekisui chemicals, POLYOX™ and Walocel™ from DowChemicals are other options.

The one or more water-soluble polymers and/or water-reactive polymersused in elastomeric material of the present invention generally have alow molecular weight. For example, the water-soluble polymers and/orwater-reactive polymers can have a number average molecular weight(M_(n)) of about 1,000 to about 80,000 grams per mole (and all valuesand ranges therebetween), in some embodiments about 5,000 to about60,000 grams per mole, and in some embodiments about 10,000 to about40,000 grams per mole. Likewise, the one or more water-soluble polymersand/or water-reactive polymers can also have a weight average molecularweight (M_(w)) of about 10,000 to about 150,000 grams per mole (and allvalues and ranges therebetween), in some embodiments from about 20,000to about 100,000 grams per mole, and in some embodiments, from about30,000 to about 75,000 grams per mole. The ratio of the weight averagemolecular weight to the number average molecular weight (M_(w)/M_(n)),i.e., the “polydispersity index”, is also relatively low. For example,the polydispersity index is typically about 1 to about 4 (and all valuesand ranges therebetween), in some embodiments about 1.1 to about 3, andin some embodiments about 1.2 to about 2.5. The water-soluble polymersand/or water-reactive polymers may also have a solution viscosity ofabout 50 to about 800 milliPascal seconds (mPas) (and all values andranges therebetween), in some embodiments about 100 to about 700 mPas,and in some embodiments about 200 to about 600 mPas. The solutionviscosity is measured as a 4 percent aqueous solution at 20° C. by theHoeppler falling ball method in accordance with ASTM-D 1343-56 Part 8,1958, page 486

Some polymers are known to degrade by solvolysis (primarily hydrolysis)in high temperature, high pressure fluid (water) systems. Step-growthpolymers like polyesters, polyamides and polycarbonates can be degradedby solvolysis and mainly hydrolysis to give lower molecular weightmolecules. Polyamide is particularly sensitive to degradation by acidsand high temperature water, as the reverse reaction of the synthesis ofthe polymer:

During hydrolysis, there is a chemical reaction with the polymer chain,causing the polymer to break down into water-soluble units. Threemechanisms are known, consisting of breaking crosslinks to allowsolvation, breaking-side chains to create hydrophilic units that becomesoluble, or breaking regular bonds causing the formation of smallmolecular weight monomers that are water soluble. Some of these types ofhydrolysis reactions are illustrated in FIG. 1.

The relative amount of the water-soluble polymers and/or water-reactivepolymers and elastomer used in the elastomeric material of the presentinvention can also be selected to minimize phase separation. Forexample, the weight ratio of the water-soluble polymers and/orwater-reactive polymers to the elastomer can be about 0.01 to about 3(and all values and ranges therebetween), in some embodiments about 0.1to about 2.5, and in some embodiments about 1 to about 2.

In one non-limiting embodiment, one or more of the water-solublepolymers and/or water-reactive polymers that are used in the elastomericmaterial are selected from the group consisting of Poly(vinyl alcohol)(PVA), Polyethylene glycol (PEG), Polyglycolide (PGA), Poly(lactic acid)(PLA), polysaccharides, collagen, polyvinylpyrrolidone, hydroxyethylacrylate or methacrylate, hydroxypropyl acrylate or methacrylate,acrylic or methacrylic acid, acrylic or methacrylic esters or vinylpyridine, acrylamide, vinyl acetate, vinyl alcohol, and ethylene oxide.

C. Optional Components

The elastomeric material can include one or more optional components.The use of one or more optional component can create one or moreadditional phases in the elastomeric material; however, this is notrequired. When the one or more optional components are insoluble withthe elastomer and the water-soluble polymer and/or water-reactivepolymer, an additional phase in the elastomeric material may be formed.The use of the one or more optional components is generally used toimprove the mechanical properties of the composite material.

The optional components include plasticizer, compatibilizer, binder,polyester, filler, adhesion additions, reactive and/or swellableadditive. The content of the one or more optional components in theelastomeric material (when used) is about 1 vol. % to 60 vol. % (and allvalues and ranges therebetween), typically about 2 vol. % to 40 vol. %,and more typically about 3 vol. % to 30 vol. %. One or more of theoptional components can optionally be dissolvable or degradable byhydrolysis.

1. Plasticizer

A plasticizer can optionally be used in the elastomeric material of thepresent invention. The plasticizer (when used) can facilitate inrendering the water-soluble polymer melt-processible. Typically, theweight ratio of the water-soluble polymer to the plasticizer (when used)is about 1-50:1 (and all values and ranges therebetween), typicallyabout 2-25:1, and more typically about 3-15:1. The plasticizer contentin the elastomeric material of the present invention (when used) isgenerally about 1 vol. % to about 40 vol. % (and all values and rangestherebetween), typically about 2 vol. % to about 30 vol. %, moretypically 5 vol. % to about 25 vol. %, and even more typically about 5vol. % to about 15 vol. %.

Suitable plasticizers include, but are not limited to, polyhydricalcohol plasticizers, such as, but not limited to, sugars (e.g.,glucose, sucrose, fructose, raffinose, maltodextrose, galactose, xylose,maltose, lactose, mannose, and erythrose), sugar alcohols (e.g.,erythritol, xylitol, malitol, mannitol, and sorbitol), polyols (e.g.,ethylene glycol, glycerol, propylene glycol, dipropylene glycol,butylene glycol, and hexane triol), manganese chloride tetrahydrate,magnesium chloride hexahydrate etc. Other suitable plasticizers arehydrogen bond-forming organic compounds which do not have hydroxylgroup, including, but not limited to, urea and urea derivatives;anhydrides of sugar alcohols such as, but not limited to, sorbitan;animal proteins such as, but not limited to, gelatin; vegetable proteinssuch as, but not limited to, sunflower protein, soybean proteins, cottonseed proteins; and mixtures thereof. Other suitable plasticizers caninclude phthalate esters, dimethyl and diethylsuccinate and relatedesters, glycerol triacetate, glycerol mono and diacetates, glycerolmono, di, and tripropionates, butanoates, stearates, lactic acid esters,citric acid esters, adipic acid esters, stearic acid esters, oleic acidesters, and other acid esters. Aliphatic acids can also be used, suchas, but not limited to, copolymers of ethylene and acrylic acid,polyethylene grafted with maleic acid, polybutadiene-co-acrylic acid,polybutadiene-co-maleic acid, polypropylene-co-acrylic acid,polypropylene-co-maleic acid, and other hydrocarbon based acids. A lowmolecular weight plasticizer is typically selected, such as less thanabout 20,000 g/mol, typically less than about 5,000 g/mol and moretypically less than about 1,000 g/mol.

Through selective control over the nature of the water-soluble polymer(e.g., molecular weight, viscosity, etc.), the nature of theplasticizer, and the relative amounts of the water-soluble polymer andplasticizer, the resulting plasticized water-soluble polymer can achievea melt viscosity that is similar to that of the elastomer, which furtherhelps minimize phase separation during formation of the elastomericmaterial. In one non-limiting embodiment, the ratio of the meltviscosity of the elastomer to the plasticized water-soluble polymer isabout 0.6 to about 2.5 (and all values and ranges therebetween), in someembodiments about 0.8 to about 2.2, and in some embodiments about 0.9 toabout 2. For example, the plasticized water-soluble polymer can have anapparent melt viscosity of about 10 to about 400 Pascal seconds (Pas)(and all values and ranges therebetween), in some embodiments about 20to about 200 Pas, and in some embodiments about 30 to about 80 Pas, asdetermined at a temperature of 195° C. and a shear rate of 1000 sec⁻¹.Likewise, the apparent melt viscosity of the elastomer can be about 20to about 500 Pascal seconds (Pas) (and all values and rangestherebetween), in some embodiments about 30 to about 200 Pas, and insome embodiments about 40 to about 100 Pas, as determined at atemperature of 195° C. and a shear rate of 1000 sec⁻¹.

The plasticizer can be optionally added to form a single phase in thebinder or interfacial phase between the water-soluble polymer and theelastomer.

2. Compatibilizer

One or more compatibilizers can also be used in the elastomeric materialto further enhance the compatibility between the elastomeric phase andthe water-soluble polymer in the elastomeric material. When used, suchcompatibilizer typically constitutes about 1 vol. % to about 20 vol. %of the elastomeric material (and all values and ranges therebetween),typically about 1 vol. % to about 15 vol. %, and more typically about 2vol. % to 10 vol. %. Non-limiting examples of compatibilizers includeboth homopolymers and copolymers, i.e., polyethylene, ethylenecopolymers such as, but not limited to, polypropylene, propylenecopolymers, and polymethylpentene polymers. An olefin copolymer caninclude a minor amount of non-olefinic monomers, such as, but notlimited to, styrene, vinyl acetate, diene, or acrylic and non-acrylicmonomer.

Non-limiting examples of compounds containing functional groups actingas compatabilizers include, but are not limited to, aliphatic carboxylicacids; aromatic carboxylic acids; esters; acid anhydrides and acidamides of these acids; imides derived from these acids and/or acidanhydrides; aliphatic glycols or phenols; isocyanates, such as, but notlimited to, toluene diisocyanate and methylenebis-(4-phenyl isocyanate);oxazolines, such as, but not limited to, 2-vinyl-2-oxazoline; epoxycompounds, such as, but not limited to, epichlorohydrin and glycidylmethacrylate; aliphatic amines (e.g., monoamines, diamines, amines, ortetramines); aromatic amines, such as, but not limited to,m-phenylenediamine; and so forth. Particularly suitable functionalgroups are maleic anhydride, maleic acid, fumaric acid, maleimide,maleic acid hydrazide, a reaction product of maleic anhydride anddiamine, methylnadic anhydride, dichloromaleic anhydride, maleic acidamide and, natural fats and oils such as, but not limited to, soybeanoil, tung oil, caster oil, linseed oil, hempseed oil, cottonseed oil,sesame oil, rapeseed oil, peanut oil, camellia oil, olive oil, coconutoil and sardine oil; unsaturated carboxylic acid such as, but notlimited to, acrylic acid, butenoic acid, crotonic acid, vinyl aceticacid, methacrylic acid, pentenoic acid, angelic acid, tiglic acid,2-pentenoic acid, 3-pentenoic acid, .alpha.-ethylacrylic acid,.beta.-methylcrotonic acid, 4-pentenoic acid, 2-methyl-2-pentenoic acid,3-methyl-2-pentenoic acid, oc-ethylcrotonic acid,2,2-dimethyl-3-butenoic acid, 2-heptenoic acid, 2-octenoic acid,4-decenoic acid, 9-undecenoic acid, 10-undecenoic acid, 4-dodecenoicacid, 5-dodecenoic acid, 4-tetradecenoic acid, 9-tetradecenoic acid,9-hexadecenoic acid, 2-octadecenoic acid, 9-octadecenoic acid,eicosenoic acid, docosenoic acid, erucic acid, tetracocenoic acid,mycolipenic acid, 2,4-pentadienic acid, 2,4-hexadienic acid, diallylacetic acid, geranic acid, 2,4-decadienic acid, 2,4-dodecadienic acid,9,12-hexadecadienic acid, 9,12-octadecadienic acid, hexadecatrienicacid, linolic acid, linolenic acid, octadecatrienic acid, eicosadienicacid, eicosatrienic acid, eicosatetraenic acid, ricinoleic acid,eleosteric acid, oleic acid, eicosapentaenic acid, erucic acid,docosadienic acid, docosatrienic acid, docosatetraenic acid,docosapentaenic acid, tetracosenoic acid, hexacosenoic acid,hexacodienoic acid, octacosenoic acid, and tetraaconitic acid; ester,acid amide or anhydride of these unsaturated carboxylic acid above; etc.

Maleic anhydride-modified polyolefins are particularly suitable for usein compatabilizing olefinic elastomers and water soluble binders. Suchmodified polyolefins are typically formed by grafting maleic anhydrideonto a polymeric backbone material. Such maleated polyolefins areavailable from E. I. du Pont de Nemours and Company under thedesignation Fusabond®, such as, but not limited to, the P Series(chemically-modified polypropylene), E Series (chemically-modifiedpolyethylene), C Series (chemically-modified ethylene vinyl acetate), ASeries (chemically-modified ethylene acrylate copolymers orterpolymers), or N Series (chemically-modified ethylene-propylene,ethylene-propylene diene monomer (EPDM) or ethylene-octene).Alternatively, maleated polyolefins are also available from ChemturaCorp. under the designation Polybond® and Eastman Chemical Company underthe designation Eastman G™ series.

3. Other Components

One or more other components can optionally be incorporated into theelastomeric material. In one non-limiting embodiment, the elastomericmaterial can include a binder material such as a starch. Modifiedstarches, for instance, can be used that have been chemically modifiedby typical processes known in the art (e.g., esterification,etherification, oxidation, enzymatic hydrolysis, etc.). Starch ethersand/or esters such as, but not limited to, hydroxyalkyl starches,carboxymethyl starches, etc., can be particularly desirable.Representative hydroxyalkyl starches such as, but not limited to,hydroxyethyl starch, hydroxypropyl starch, hydroxybutyl starch, andderivatives thereof can be used. Starch esters, for instance, can beprepared using a wide variety of anhydrides (e.g., acetic, propionic,butyric, and so forth), organic acids, acid chlorides, or otheresterification reagents. The degree of esterification can vary asdesired, such as from 1 to 3 ester groups per glucosidic unit of thestarch. The starch, when used, is generally present at about 0.1 vol.%-40 vol. % (and all values and ranges therebetween), typically at about0.2 vol. %-30 vol. %, more typically about 1 vol. %-20 vol. %, stillmore typically 1 vol. %-15 vol. %, and yet more typically 2 vol. %-10vol. %.

Furthermore, the elastomeric material can optionally contain one or morebiodegradable polyesters. Examples of suitable biodegradable polyestersinclude aliphatic polyesters, such as, but not limited to,polycaprolactone, polyesteramides, modified polyethylene terephthalate,polylactic acid (PLA) and its copolymers, terpolymers based onpolylactic acid, polyglycolic acid, polyalkylene carbonates (such aspolyethylene carbonate), polyhydroxyalkanoates (PHA),poly-3-hydroxybutyrate (PHB), poly-3-hydroxyvalerate (PHV),poly-3-hydroxybutyrate-co-4-hydroxybutyrate,poly-3-hydroxybutyrate-co-3-hydroxyvalerate copolymers (PH BV),poly-3-hydroxybutyrate-co-3-hydroxyhexanoate,poly-3-hydroxybutyrate-co-3-hydroxyoctanoate,poly-3-hydroxybutyrate-co-3-hydroxydecanoate,poly-3-hydroxybutyrate-co-3-hydroxyoctadecanoate, and succinate-basedaliphatic polymers (e.g., polybutylene succinate, polybutylene succinateadipate, polyethylene succinate, etc.); aromatic polyesters and modifiedaromatic polyesters; and aliphatic-aromatic copolyesters. The polyester(when used) is generally present at about 0.1-40 vol. % (and all valuesand ranges therebetween), typically at about 0.2-30 vol. %, moretypically about 1-20 vol. %, still more typically 1-15 vol. %, and yetmore typically 2-10 vol. %.

Other optional components can include fillers, such as carbon black orsilica which modify the properties of the material or reduce cost. Theaddition of silica, carbon black, and other fillers into the rubber orsoluble polymer phase can be used to increase its hardness and wearresistance, or modify its frictional properties (e.g., through theaddition of MoS2) to achieve a desired end result. The filler (whenused) is generally present at about 0.1-40 vol. % (and all values andranges therebetween), typically at about 0.2-30 vol. %, more typicallyabout 1-20 vol. %, still more typically 1-15 vol. %, and yet moretypically 2-10 vol. %.

Formulations of the elastomeric material can sometimes require somemodest stress to completely break up the residual structure (e.g., thedissolvable rubber loses cohesion, but does not generally disperseunless there is some mechanical force applied, which can be an impact, aslight flow, etc.). Generally, the less force required to completelydisperse the particle of elastomer (e.g., rubber particles, etc.), themore successful and acceptable the formulation. This requirement foradded force can be largely alleviated through the addition of reactive,and/or swellable (R/S) additions which react with the fluid thatelastomeric material is exposed to so as to generate stress throughexpansion, reaction, gas generation, etc. Examples of such materialsinclude the addition of CaO, which hydrates in water to expand, whichcan apply a force to break up the dissolvable rubber. Other examples ofmaterials include clays, borohydrates, aluminum-gallium alloy particles,magnesium or magnesium alloy particles or flakes, magnesium oxide, iron,silicon, zinc, aluminum, aluminum alloy, magnesium, magnesium alloy thatundergoes a volume change, gas generating reaction, decomposition,reaction, or other force-generating interaction upon exposure to water,brine and/or oil, or other type of fluid environment sufficient toaccelerate the dispersion of the rubber in the elastomeric material. Thereactive and/or swellable addition (when used) is generally present atabout 0.1-35 vol. % (and all values and ranges therebetween), typicallyat about 0.2-25 vol. %, more typically about 1-20 vol. %, still moretypically 1-15 vol. %, and yet more typically 2-10 vol. %.

In one non-limiting embodiment, the one or more optional componentsinclude manganese chloride tetrahydrate, magnesium chloride hexahydrate,and/or glycerol. In another and/or additional non-limiting embodiment,the one or more optional components include a material that undergoes avolume change, gas-generating reaction, decomposition, reaction, and/orother force-generating interaction upon exposure to fluid about saidcomposite material, said secondary components formulated to facilitatein a break-up and/or dispersion of said second material in saidcomposite material. In another and/or additional non-limitingembodiment, the one or more optional components include one or morecomponents selected from the group consisting of manganese chloridetetrahydrate, magnesium chloride hexahydrate, and glycerol. In anotherand/or additional non-limiting embodiment, the one or more optionalcomponents include one or more components selected from the groupconsisting of magnesium alloys, aluminum alloys, oxides, carbonates,nickel-containing alloys, and/or iron-based alloys. In another and/oradditional non-limiting embodiment, the one or more optional componentsinclude one or more components selected from the group consisting ofcalcium oxide, magnesium oxide, iron, silicon, zinc, aluminum, aluminumalloy, magnesium, and magnesium alloy. In another and/or additionalnon-limiting embodiment, the one or more optional components include oneor more components selected from the group consisting of carbon black,glass fiber, fumed silica or other high surface area material, and/orwhich can be flake or fibrous in nature, and which can optionally alsobe used to add color. In another and/or additional non-limitingembodiment, the one or more optional components include acompatibilizer, adhesion addition, or combinations thereof. In anotherand/or additional non-limiting embodiment, the one or more optionalcomponents include one or more components selected from the groupconsisting of polyvinylpyrrolidone (PVP), MnCl₂.4H₂O and MgCl₂.6H₂O,which components optionally tie or bind together the elastomer and thewater-soluble polymer and/or water-reactive polymer.

The composite material can be processed so as to allow controlledcontiguity (touching of the particles) of the elastomer from 0%(elastomer fully dispersed in composite material) to 70% or more (theelastomer is clustered in the composite material). Generally, thecomposite material is processed so that the elastomer is from 0% to 30%contiguity. The degree of contiguity of the elastomer can be controlledby various processes such as agglomeration, coating, pre-pressing, sigmablending, dry-blending, or other controlled mixing or blending techniquethat can control the degree of mixing of the elastomer with thewater-soluble polymer and/or water-reactive polymer.

The composite material can be formulated to be moldable into a finalshape, bulk moldable, and/or machinable into a final shape.

The composite material is generally formulated to dissolve or hydrolyzein water or in a water-based solution at an appreciable rate (e.g., atleast 10% dissolution or hydrolyzation in a 2-3 hour period) only atelevated temperatures (e.g., temperature of 55° C. or greater).

The composite material is generally formulated to exhibit a shore Ahardness of 70-99 (ASTM D2240-15), and typically 82-92. The compositematerial has a limited compressive set (e.g., 20-85% and all values andranges therebetween), and typically below 50% (ASTM D395-16e1).

The composite material can be formulated to begin breaking down byinitial swelling before dissolution; however, this is not required. Suchswelling can occur in the phase formed of the water-soluble polymerand/or water-reactive polymer, and then followed by dissolution in thewater-soluble polymer and/or water-reactive polymer. The swelling can becaused by hydration, carbonation, and/or oxidation of one or morematerials in the composite material (e.g., CaO, MgO, Fe, Mg, Li, Ca, Zn,montmorrilinate, clay, polyacrylate, or other water-swellable expandablematerials). Also or alternatively, the water-soluble polymer and/orwater-reactive polymer can be formulated to swell, expand, and/or reactto cause expansion in water at a rate faster than, or at a hightemperature than, the dissolution or degradation of the water-solublepolymer and/or water-reactive polymer.

The composite material can optionally include a coating material that isformulated to degrade by one or more means selected from the groupconsisting of exposure to at least a predetermined temperature, after acertain time period, exposure to a certain chemical, exposure toelectricity, exposure to a certain electromagnetic wave. Such coatingpartially or fully encapsulates the other components of the compositematerial. The coating can be a flexible coating; however, this is notrequired. The coating is generally formed of a polymer or metalmaterial. The coating can be used to control when and/or the rate ofdissolution and/or degradation of the composite material.

The composite material includes a binder. The binder can have adifferential solubility such that it dissolves very slowly attemperatures below about 50° C. to about 70° C., and at a higher rateabove 70° C. to 150° C. and any value or range therebetween. The bindercan include a starch such as a modified starch.

In summary, the invention is directed to a degradable, elastomericcomposite material comprised of a continuous matrix of at least twophases. A first phase includes a first material and a second phaseincludes a second material. The continuous matrix has a desiredelastomeric property set that defines the overall mechanical andelastomeric properties of the composite material. The first material isa polymer that is dissolvable in a fluid, degradable in a fluid, orcombinations thereof and constitutes about 5 vol. % to about 60 vol. %of the composite material. The second material includes one or moreelastomers and constitutes about 5 vol. % to about 90 vol. % of thecomposite material. The first material can be a) a water-soluble polymerhaving low solubility below about 30° C. and increased solubility atabout 70° C.-130° C., or b) a polymer that is degradable by hydrolysisor solvates into soluble elements such as monomers or chemically alteredsoluble polymers. The first material can be selected to have anacceptable degradation rate at 55° C., 70° C., 100° C., 135° C., or 180°C., and has low reactivity at temperatures below about 30° C. The firstmaterial can be a liquid-soluble polymer including one or more materialsselected from the group consisting of poly(vinyl alcohol) (PVA),polyethylene glycol (PEG), polyglycolide (PGA), poly(lactic acid) (PLA),polysaccharides, collagen, polyvinyl pyrrolidone, hydroxyethyl acrylateor methacrylate, hydroxypropyl acrylate or methacrylate, acrylic ormethacrylic acid, acrylic or methacrylic esters or vinyl pyridine,acrylamide, vinyl acetate, vinyl alcohol, and ethylene oxide. The secondmaterial can include one or more materials selected from the groupconsisting of natural rubber, vulcanized rubber, silicone, polyurethane,synthetic rubber, polybutadiene, nitrile rubber (NBR), polyisobutylene,acrylate-butadiene rubber, and styrene butadiene rubber. The compositematerial can further include one or more secondary components selectedfrom the group consisting of plasticizer, compatibilizer, binder,polyester, filler, adhesion additions, reactive and/or swellableadditive. The secondary component can be dissolvable or degradable byhydrolysis. The secondary component can form a third phase in thecomposite material. The secondary component can include a material thatundergoes a volume change, gas generating reaction, decomposition,reaction, and/or other force-generating interaction upon exposure tofluid about said composite material. The secondary component can beformulated to facilitate in a break-up and/or dispersion of the secondmaterial in the composite material. The secondary component can includeone or more components selected from the group consisting of manganesechloride tetrahydrate, magnesium chloride hexahydrate, and glycerol. Thesecondary component can include one or more components selected from thegroup consisting of magnesium alloys, aluminum alloys, oxides,carbonates, nickel-containing alloys, and/or iron-based alloys. Thesecondary component can include one or more components selected from thegroup consisting of calcium oxide, magnesium oxide, iron, silicon, zinc,aluminum, aluminum alloy, magnesium, and magnesium alloy. The secondarycomponent can include one or more components selected from the groupconsisting of carbon black, glass fiber, and fumed silica. The secondarycomponent can include a compatibilizer, adhesion addition, orcombinations thereof. The secondary component can include one or morecomponents selected from the group consisting of polyvinylpyrrolidone(PVP), MnCl₂.4H₂O and MgCl₂.6H₂O to tie or bind together the continuousmatrix and second material. The secondary component can includeplasticizer. The plasticizer can constitute about 1 vol. % to about 40vol. % of the composite material. The secondary component can include amaterial formulated to swell before dissolution of said first material.The secondary component can include one or more materials selected fromthe group consisting of CaO, MgO, Fe, Mg, Li, Ca, Zn, montmorrilinate,clay, and polyacrylate. The composite material can derive at least about80% of its hardness and mechanical response from the second material.The composite material can further include a coating material. Thecoating material can be formulated to degrade by one or more meansselected from the group consisting of exposure to at least apredetermined temperature, after a certain time period, exposure to acertain chemical, exposure to electricity, exposure to a certainelectromagnetic wave. The composite material can have a tensile strengthof greater than about 500-2000 psig (ASTM D412), and typically greaterthan about 3500 psig. The composite material can have an ultimateelongation of at about 20%-200% (ASTM D412) (and all values and rangestherebetween), and typically about 75% and 115%. The composite materialcan be formulated to be as suitable for use as a sealing element,packer, or other downhole sealing component. The composite material canbe formulated to be storable at about 30° C.-40° C. for an extendedperiod of time (e.g., at least one month) once the parts are vacuumsealed so as to exhibit little or no degradation during storage (lessthan 1% degradation), and can be formulated to be thermally stable attemperatures of up to 140° C., and typically up to about 200° C. whilein storage. The formed composite material can optionally be coated witha hydrophobic material to prevent premature degradation during handlingand storage.

General formulations of the dissolvable elastomeric material in volumepercent in accordance with the present invention as follows:

Ingredients Ex. 1 Ex. 2 Ex. 3 Ex. 4 Elastomer 10%-90%  15%-80%  20%-75% 15%-60%  WS or WR 5%-60% 10%-45%  20%-40%  20%-35%  Polymer Plasticizer0%-40% 2%-30% 5%-25% 5%-15% Compatibilizer 0%-20% 1%-20% 1%-15% 2%-10%Binder 0%-20% 1%-20% 1%-15% 2%-10% Polyester 0%-20% 1%-20% 1%-15% 2%-10%Filler 0%-20% 1%-20% 1%-15% 2%-10% R/S Additive 0%-20% 1%-20% 1%-15%2%-10%

Non-limiting specific examples of the dissolvable elastomeric materialin accordance with the present invention are as follows:

EXAMPLE 5

A dissolvable elastomeric material in accordance with the presentinvention formed of about 70 vol. % polyurethane rubber particles 30-100μm in size bonded together in a plasticized PVOH matrix was found tohave the same elongation to failure, tensile strength and compressionstrength as the original polyurethane rubber. At lower temperatures, theelastomeric material composite was able to be used in a similar manneras a part made of 100% polyurethane. The elastomeric material wassubmerged in about 185° F. (85° C.) fresh water and over 70% of theelastomeric material dissolved in about 5 hours leaving a 30-100 μmpowder and a flowable medium viscosity liquid.

EXAMPLE 6

A dissolvable elastomeric material in accordance with the presentinvention formed of about 60 vol. % recycled vulcanized rubber particlesabout 100-1000 μm in diameter, about 30 vol. % PEG plasticized PLA asthe matrix and about 10 vol. % glass fiber reinforcement was molded intoa solid structure. The elastomeric material had tensile and hardnessvalues within about 20% of the recycled vulcanized rubber material. Theelastomeric material was placed in water and no degradation was seen atunder about 122° F. (50° C.). Between about 122° F. (50° C.) and 212° F.(100° C.), over 70% of the elastomeric material dissolved in the heatedwater over about 30 hours resulting in a flowable mixture of about100-1000 μm (and all values and ranges therebetween) rubber particlesand a higher viscosity liquid.

EXAMPLE 7

A dissolvable elastomeric material in accordance with the presentinvention formed of about 75 vol. % polyurethane particles about 30-100μm in size was bonded together in a PEG matrix. The elastomeric materialwas then coated with a flexible polysiloxane coating. The elastomericmaterial had properties within about 30% in durometer and compressivestrength compared to the base polyurethane material. The elastomericmaterial was placed in about 194° F. (90° C.) water for 24 hours with nodegradation or change to the mechanical properties of the elastomericmaterial. The elastomeric material was then placed into about 194° F.(90° C.) water for about 6 hours and then a chemical trigger thatremoved the polysiloxane coating was added. Over 70% of the elastomericmaterial then dissolved away in one hour leaving about 30-100 umpolyurethane particles in a low viscosity liquid.

EXAMPLE 8

A dissolvable elastomeric material in accordance with the presentinvention was formed of about 70 vol. % nitrile butadiene rubber, 18vol. % poly vinyl alcohol, 3 vol. % glycerol, and 9 vol. % MnCl₂.4H₂O.The hardness of the material was found to be between 78-95 Shore A. Thecompression set property according to ASTM D 395 was measured to bebetween 5%-60%. The material was placed in 3% KCl with temperaturesranging between 130° F. (54° C.)-150° F. (66° C.) and over 70% of thematerial was degraded in-between 10-20 hours. The thermoplastic meltsinto powdered NBR at 300° F. (150° C.)-392° F. (200° C.). The variationon the hardness w.r.t dissolution is illustrated in FIGS. 2A-2C. Thedissolvable elastomeric material can also be used as a material for 3Dprinter as illustrated in FIGS. 3-4. FIG. 3 illustrated an extrudedfilament material formed of the dissolvable elastomeric material inaccordance with the present invention. FIG. 4 represents a 3D printedseal that was formed by the extruded filament material. The extrudedfilament material was exposed to a temperature of about 374° F. (190°C.) when forming the seal. The final seal has an OD of about 4 inchesand an ID of about 3 inches.

The mechanical properties of the formed seal was tested according to thefollowing ASTM standards and was measured as follows:

Mechanical Property Test Method Result Tear Strength ASTM D624   32.1 ±2.15 kN/m Tensile Strength @ Yield ASTM D 412  722.29 ± 23.2 psi TensileStrength @ Break ASTM D 412 807.86 ± 49.31 psi Tensile Elongation @BreakASTM D 412 28.1 ± 7.71% Tensile Elongation @ Yield ASTM D 412 18.4 ±3.39% Compression Set @ 22 hr ASTM D 395B 75% Compression Set @ 70 hrASTM D 395B 78%

Mechanical properties of the seal were also measured at 149° F., 194°F., 275° F. and 302° F. and the results are as follows:

149° F. 194° F. 275° F. 302° F. Properties (65° C.) (90° C.) (135° C.)(150° C.) Tensile @ 123.71 ± 22.62 64.54 ± 5.95 41.62 ± 5.07 49.6 ± 3.19Break Elongation   237 ± 20.6   176 ± 3.67   151 ± 15.4  146 ± 19.7 @Break Compression 90.02%  91.6% 94.69% Not Tested Set @ 22 hrsCompression 94.27% 93.47%   100% Not Tested Set @ 70 hrs

EXAMPLE 9

A dissolvable elastomeric material in accordance with the presentinvention was formed of about 60 vol. % nitrile butadiene rubber, 16vol. % poly vinyl alcohol, 8 vol. % glycerol, and 16 vol. %polyvinylpyrrolidone. The hardness of the material was found to bebetween 78-95 Shore A. The compression set property according to ASTM D395 was measured to be between 5-60%. The material was placed in 3% KClwith temperatures ranging between 130 F-150° F. and over 70% of thematerial was degraded in-between 10-20 hours. The degraded elastomericmaterial was easy to break by hand. The variation on the hardness withrespect to dissolution is illustrated in FIGS. 5A-5C. FIG. 6 representsa seal that was formed from the elastomeric material. The final seal hasan OD of about 4 inches and an ID of about 3 inches.

EXAMPLE 10

A dissolvable elastomeric material in accordance with the presentinvention was formed of about 50 vol. % nitrile butadiene rubber, 47.5vol. % poly vinyl alcohol 47.5 vol. %, and 2.5 vol. % glycerol. Thehardness of the material was found to be between 78-95 Shore A. Thecompression set property according to ASTM D 395 was measured to bein-between 5%-60%.

EXAMPLE 11

A dissolvable elastomeric material in accordance with the presentinvention was formed with 70 vol. % nitrile butadiene rubber, 10 vol. %glycerol, 8 vol. % PVP/MnCl₂ and 4 vol. % calcium oxide. The hardness ofthe material ranges between 60 and 80 Shore A. The compression setproperty according to ASTM D 395 was measured to be between 5%-60%. Thematerial was placed in 3 vol. % KCl with temperatures ranging between130° F.−150° F. and over 70% of the material was degraded between 10-20hours into particles under size of 0.5 mm.

FIGS. 7-9 illustrate various non-limiting elastomeric materials inaccordance with the present invention. FIG. 7 illustrates an elastomericmaterial formed from elastomeric particles (12) in a dissolvable matrix(10). FIG. 8 illustrates an elastomeric material formed from elastomericparticles (16) in a water soluble matrix (14) with the entire compositesurrounded by a protective coating (18). The outer coating is generallyformulated to be triggered or removed by some method (e.g., pH change,change in surrounding fluid composition, electrical charge, exposure tomagnetic field, pressure change, exposure to a certain electromagneticwave, exposure to ultrasonic waves, etc.). FIG. 9 illustrates anelastomeric material formed from a dissolving matrix (20) withelastomeric particles (22) and mechanically reinforcement from particlesor fibers (24).

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained, andsince certain changes may be made in the constructions set forth withoutdeparting from the spirit and scope of the invention, it is intendedthat all matter contained in the above description and shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense. The invention has been described with reference topreferred and alternate embodiments. Modifications and alterations willbecome apparent to those skilled in the art upon reading andunderstanding the detailed discussion of the invention provided herein.This invention is intended to include all such modifications andalterations insofar as they come within the scope of the presentinvention. It is also to be understood that the following claims areintended to cover all of the generic and specific features of theinvention herein described and all statements of the scope of theinvention, which, as a matter of language, might be said to fall therebetween. The invention has been described with reference to thepreferred embodiments. These and other modifications of the preferredembodiments as well as other embodiments of the invention will beobvious from the disclosure herein, whereby the foregoing descriptivematter is to be interpreted merely as illustrative of the invention andnot as a limitation. It is intended to include all such modificationsand alterations insofar as they come within the scope of the appendedclaims.

What is claimed:
 1. A degradable structural seal at least partiallyformed of a degradable, elastomeric composite material, said degradableelastomeric composite material comprised of a first material and asecond material, said first material is a polymer that is dissolvableand/or degradable in a fluid, said first material constitutes about 5-60vol. % of said composite material, said second material includesparticles of elastomer, said second material is disbursed in said firstmaterial, said second material constitutes about 5-80 vol. % of saidcomposite material, said particles of elastomer having a particle sizeof 30-1000 μm, said elastomer includes olefinic elastomer, ethyleneelastomer, vulcanized elastomer and/or nitrile rubber, said secondmaterial having a different composition than said first material, saidfirst material is a water-soluble and/or water-reactive polymer that hasa solubility at below about 30° C. that is less than a solubility atabout 70-130° C., said composite material formulated to have at least10% dissolution or hydrolyzation in a 2-3 hour period at a temperatureof at least 55° C.
 2. The degradable structural seal as defined in claim1, wherein said first material is a liquid-soluble polymer including oneor more materials selected from the group consisting of poly(vinylalcohol) (PVA), polyethylene glycol (PEG), polyglycolide (PGA),poly(lactic acid) (PLA), polysaccharides, collagen, polyvinylpyrrolidone, hydroxyethyl acrylate or methacrylate, hydroxypropylacrylate or methacrylate, acrylic or methacrylic acid, acrylic ormethacrylic esters or vinyl pyridine, acrylamide, vinyl acetate, vinylalcohol, and ethylene oxide.
 3. The degradable structural seal asdefined in claim 1, wherein said second material includes one or morematerials selected from the group consisting of natural rubber,vulcanized rubber, silicone, polyurethane, synthetic rubber,polybutadiene, nitrile rubber (NBR), polyisobutylene, acrylate-butadienerubber, and styrene butadiene rubber.
 4. The degradable structural sealas defined in claim 1, further including one or more secondarycomponents selected from the group consisting of plasticizer,compatibilizer, binder, polyester, filler, adhesion additions, reactiveand/or swellable additive.
 5. The degradable structural seal as definedin claim 4, wherein said secondary component is dissolvable ordegradable by hydrolysis.
 6. The degradable structural seal as definedin claim 4, wherein said secondary component forms a third phase in saidcomposite material.
 7. The degradable structural seal as defined inclaim 4, wherein said secondary component includes a material thatundergoes a volume change, gas-generating reaction, decomposition,reaction, and/or other force-generating interaction upon exposure tofluid about said composite material, said secondary componentsformulated to facilitate in a break-up and/or dispersion of said secondmaterial in said composite material.
 8. The degradable structural sealas defined in claim 4, wherein said secondary component includes one ormore components selected from the group consisting of manganese chloridetetrahydrate, magnesium chloride hexahydrate, and glycerol.
 9. Thedegradable structural seal as defined in claim 4, wherein said secondarycomponent includes one or more components selected from the groupconsisting of magnesium alloys, aluminum alloys, oxides, carbonates,nickel-containing alloys, and/or iron-based alloys.
 10. The degradablestructural seal as defined in claim 4, wherein said secondary componentincludes one or more components selected from the group consisting ofcalcium oxide, magnesium oxide, iron, silicon, zinc, aluminum, aluminumalloy, magnesium, and magnesium alloy.
 11. The degradable structuralseal as defined in claim 4, wherein said secondary component includesone or more components selected from the group consisting of carbonblack, glass fiber, and fumed silica.
 12. The degradable structural sealas defined in claim 4, wherein said secondary component includes acompatibilizer, adhesion addition, or combinations thereof.
 13. Thedegradable structural seal as defined in claim 4, wherein said secondarycomponent includes one or more components selected from the groupconsisting of polyvinylpyrrolidone (PVP), MnCl₂4H₂O and MgCl₂6H₂O to tieor bind together the continuous matrix and second material.
 14. Thedegradable structural seal as defined in claim 4, wherein said secondarycomponent includes plasticizer, said plasticizer constitutes about 1vol. % to about 40 vol. % of said composite material.
 15. The degradablestructural seal as defined in claim 4, wherein said secondary componentincludes a material formulated to swell before dissolution of said firstmaterial, said secondary component including one or more materialsselected from the group consisting of CaO, MgO, Fe, Mg, Li, Ca, Zn,montmorrilinate, clay, and polyacrylate.
 16. The degradable structuralseal as defined in claim 1, wherein said composite material derives atleast about 80% of its hardness and mechanical response from said secondmaterial.
 17. The degradable structural seal as defined in claim 1,further including a coating material, said coating material formulatedto degrade.
 18. The degradable structural seal as defined in claim 1,wherein said first material is a liquid-soluble polymer including one ormore materials selected from the group consisting of poly(vinyl alcohol)(PVA), polyethylene glycol (PEG), polyglycolide (PGA), poly(lactic acid)(PLA), polysaccharides, collagen, polyvinyl pyrrolidone, hydroxyethylacrylate or methacrylate, hydroxypropyl acrylate or methacrylate,acrylic or methacrylic acid, acrylic or methacrylic esters or vinylpyridine, acrylamide, vinyl acetate, vinyl alcohol, and ethylene oxide;said second material includes one or more materials selected from thegroup consisting of natural rubber, vulcanized rubber, silicone,polyurethane, synthetic rubber, polybutadiene, nitrile rubber (NBR),polyisobutylene, acrylate-butadiene rubber, and styrene butadienerubber.
 19. The degradable structural seal as defined in claim 4,wherein said first material constitutes about 8 vol. % to about 45 vol.% of said composite material, said second material constitutes about 15vol. % to about 80 vol. % of said composite material, said one or moreoptional secondary components constitute about 2 vol. % to about 40 vol.% of said composite material.
 20. The degradable structural seal asdefined in claim 4, wherein said first material constitutes about 20vol. % to about 40 vol. % of said composite material, said secondmaterial constitutes about 15 vol. % to about 60 vol. % of saidcomposite material, said one or more optional secondary componentsconstitute about 3 vol. % to about 30 vol. % of said composite material.21. The degradable structural seal as defined in claim 4, wherein saidone or more optional secondary components has one or more propertiesselected from the group consisting of a) dissolvable by hydrolysis, b)degradable by hydrolysis, c) forms a third phase in said compositematerial, d) undergoes a volume change upon exposure to fluid about saidcomposite material, e) undergoes a gas-generating reaction upon exposureto fluid about said composite material, f) undergoes a decompositionupon exposure to fluid about said composite material, g) undergoes areaction upon exposure to fluid about said composite material, h)undergoes a force-generating interaction upon exposure to fluid aboutsaid composite material, i) formulated to facilitate in a break-up ofsaid second material in said composite material, and j) formulated tofacilitate in a dispersion of said second material in said compositematerial.
 22. The degradable structural seal as defined in claim 4,wherein said secondary component includes one or more materials selectedfrom the group consisting of manganese chloride tetrahydrate, magnesiumchloride hexahydrate, glycerol, magnesium alloys, aluminum alloys,oxides, carbonates, nickel-containing alloys, iron-based alloy, calciumoxide, magnesium oxide, iron, silicon, zinc, aluminum, aluminum alloy,magnesium, magnesium alloy, carbon black, glass fiber, fumed silica,polyvinylpyrrolidone (PVP), MnCl₂4H₂O and MgCl₂6H₂O, lithium, calcium,montmorrilinate, clay, and polyacrylate.
 23. The degradable structuralseal as defined in claim 4, wherein said secondary component adds colorto said composite material.
 24. The degradable structural seal asdefined in claim 1, wherein said composite material has a hardness of70-99 shore A hardness.
 25. The degradable structural seal as defined inclaim 1, wherein said composite material has a hardness of 82-92 shore Ahardness.
 26. The degradable structural seal as defined in claim 1,wherein said elastomer includes olefinic elastomer, ethylene elastomer,vulcanized elastomer and/or nitrile rubber, said first materialincludes 1) vinyl alcohol polymers; 2) copolymers of vinyl alcohol; 3)monomers of vinyl pyrrolidone, hydroxyethyl acrylate, hydroxyethylmethacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate,acrylic acid, methacrylic acid, acrylic esters, acrylic vinyl pyridine,methacrylic esters, methacrylic vinyl pyridine, acrylamide, vinylacetate, vinyl alcohol, ethylene oxide, and/or polyvinylpyrrolidone; 4)polyamides; 5) polyesters; and/or 6) polycarbonates.
 27. The degradablestructural seal as defined in claim 1, wherein said first materialincludes poly(vinyl alcohol), polyethylene glycol, polyglycolide,poly(lactic acid), polysaccharides, collagen, polyvinylpyrrolidone,hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropylacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid,acrylic ester, methacrylic ester, vinyl pyridine, acrylamide, vinylacetate, vinyl alcohol, and/or ethylene oxide.
 28. The degradablestructural seal as defined in claim 1, wherein said second materialincludes one or more materials selected from the group consisting ofnatural rubber, vulcanized rubber, silicone, polyurethane, syntheticrubber, polybutadiene, nitrile rubber (NBR), polyisobutylene,acrylate-butadiene rubber, and styrene butadiene rubber.
 29. Thedegradable structural seal as defined in claim 4, wherein said secondarycomponent forms a third phase in said composite material.
 30. Thedegradable structural seal as defined in claim 4, wherein said secondarycomponent includes manganese chloride tetrahydrate, magnesium chloridehexahydrate, glycerol, magnesium alloys, aluminum alloys, oxides,carbonates, nickel-containing alloys, iron-based alloys, calcium oxide,magnesium oxide, iron, silicon, zinc, aluminum, aluminum alloy,magnesium, magnesium alloy, carbon black, glass fiber, fumed silica,polyvinylpyrrolidone (PVP), MnCl₂4H₂O, MgCl₂6H₂O, CaO, MgO, lithium,calcium, montmorrilinate, clay, and/or polyacrylate.
 31. The degradablestructural seal as defined in claim 1, further including an outerpolymer coating material, said outer polymer coating material formulatedto degrade, said outer polymer coating material encapsulating said firstand second materials.